The right way to do it would be to issue your own system.alarm.queryJournal call to match the filters on the component, which gives you access to the same underlying data.
The more efficient, but not directly supported way, would be to get a reference to the underlying table component inside the AJT component, then extract it’s model, which will have a getAlarmAt(row) field (and getRowCount() method), which would give you full access to the reconstructed alarm event and allow you to pull whatever data you want into your constructed CSV.